Gto e40 sd help!!! No start

[Mike@Vengeance]

Okay guys I need some help on this one.

2006 GTO 427 CI with a TH400. We have been running the car with a MAF and decided to go SD. I failed the MAF per the normal ways and tried many other ways to fix it.

THE ISSUE

When I make a burn or we cut the power off the car it WILL NOT START it seems until the MAF fails agian. Should it not fail immediately. I failed it per the book and tried many variables. When I do get it running I log and tune it and managed to get the dyno complete and AF good.

If I simply plug a MAF in and fire the car it starts FINE and then while it is running I unplug it. This is how I tuned it on the dyno.

Problem is this is mostly a race car and gets alot of tune adjustments at the track as well as the power gets cut off all the time. When this happens the car will not start until after many attempts and then it starts to run normal again. I go SD all the time and this is the first time I have such a issue with this. Am I missing somthing. Any help woudl be great.

Thanks guys

Here is the tune and I relize it is not failed per the book right now. I was just trying stuff.2006 GTO SD TEST.tun

[Taz]

Hello Evilz28nos,

As a disclaimer ... I don't do any E40 tuning. The typical technique (LS1-B, E38) to run in SD is have the PCM / ECM MAF diagnostics active (but the MILs turned off), then adjust the MAF frequencies (generally reversed) such that the PCM / ECM diagnostics "fail" the MAF, and then default to the VE (or VVE) table for fueling calculations.

You had altered the MAF diagnostics - so perhaps the ECM wasn't failing the MAF. Also you had adjusted the MAF Rationality tests - I have never needed to do this to run in SD.

For proper fueling you will still require an IAT input to the ECM. Most often during SD tuning the MAF signal wire (typically yellow) is removed from the MAF connector, which still affords an IAT signal to the ECM. I have had people claim they simply unplugged the MAF & IAT - and the engine ran "fine". I have never experimented with tuning without an IAT signal - so I'm not certain about these types of claims.

Give the tune attached below a try ... it may not make any difference.


Regards,
Taz

[Mike@Vengeance]

Hello Evilz28nos,

As a disclaimer ... I don't do any E40 tuning. The typical technique (LS1-B, E38) to run in SD is have the PCM / ECM MAF diagnostics active (but the MILs turned off), then adjust the MAF frequencies (generally reversed) such that the PCM / ECM diagnostics "fail" the MAF, and then default to the VE (or VVE) table for fueling calculations.

You had altered the MAF diagnostics - so perhaps the ECM wasn't failing the MAF. Also you had adjusted the MAF Rationality tests - I have never needed to do this to run in SD.

For proper fueling you will still require an IAT input to the ECM. Most often during SD tuning the MAF signal wire (typically yellow) is removed from the MAF connector, which still affords an IAT signal to the ECM. I have had people claim they simply unplugged the MAF & IAT - and the engine ran "fine". I have never experimented with tuning without an IAT signal - so I'm not certain about these types of claims.

Give the tune attached below a try ... it may not make any difference.


Regards,
Taz

Thanks for your help and I will try it here in the next few minutes. The tune I posted will probably have many things as far as Failing the MAF wrong. I tried per the normal ways and go no where. After 8-10 hours of beating my head in the wall I started trying all kinds of stuff.

I will run the tune and let you know.

Thanks so much

[Mike@Vengeance]

Okay gave the TAZ tune a shot and NO LUCK :(

The car does have the IAT relocated and it works.

Any more ideas boys.

Cranking SPARK or Cranking VE could this be it ???

[Taz]

Just looked at your tune again ... missed your B2001 and B2002 values ... these are set for a "MAF only" type tune (like when AutoMAF tuning). Try setting B2001 to 5000 RPM and B2002 to 4900 RPM.


Regards,
Taz

[Taz]

Did you get the SD tune to work ?


Regards,
Taz